138 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIO. 
the Museum of Comparative Zodlogy, Cambridge, Mass., the first three pairs of 
ribs have capitular processes; in the Gloucester (Mass.) specimen, the 2d and 3d 
pairs; in No. 16045, U. S. N. M., Cape Cod, Mass., the 2d, 3d, and 4th pairs. 
In the type of ZB. tectirostris (Cope) the 1st rib is double-headed, as shown in 
pl. 4, fig. 4, and pl. 6, fig. 8. The rib is 30} in. long (straight) to the middle point 
of the broad distal end ; the breadth at the distal end, 74 in. The supplementary 
head is 64 in. long in a straight line, and 2} in. broad at the free end. A pre- 
cisely similar first rib is described by Van Beneden as occurring in the Borselaer 
specimen (4, 27-30, fig.). This peculiarity was formerly considered of specific 
or even generic importance, but recent investigations, especially those of Sir Wm. 
Turner, lead to the conclusion that this conformation is properly to be regarded as 
an individual variation (see Turner, Journ. Anat. and Phys., 5, 1871, pp. 348-361). 
CHARACTERS OF VERTEBR2. 
The number of vertebrve in B. physalus has already received attention (p. 134). 
The characters of the cervical vertebrae given by Flower in the diagnosis cited in a 
previous page (p. 131) are found in American specimens (see Dwight, 35, 213-217, 
pl. 1, and this work, pl. 4, fig. 4, and pl. 5, fig. 1, type of SB. tecttrostris Cope). 
Struthers (86, 32) gives as characteristic of the 3d to the 7th cervicals of adult 
B. physalus the following : 
3d and 4th. ‘Transverse processes slanting obliquely backward. 
5th. Transverse processes directed horizontally outward. 
6th. Transverse process directed a little forward. Inferior transverse process 
usually more or less incomplete. 
7th. Superior transverse process robust; inferior transverse process almost 
entirely absent. 
These characters were found in the Gloucester (Mass.) specimen described by 
Dwight (35, 218, 217, figs. 5-7), and occur also in No. 16045, U.S. N. M., Cape 
Cod, Mass. 
Among the characters of the caudal vertebrae which may be considered impor- 
tant are the positions in which the foramina and processes appear or disappear. 
Some of these points in European and American specimens are brought together in 
the following table : 
BALAINOPTERA PHYSALUS (L.). EUROPEAN AND AMERICAN. CHARACTERS OF VERTEBR-®. 
| 
| | ] 
Falmouth, St. Vigor,|Langrune, Danze Gravesend,| Nairn, ||(Mus.Comp.|Gloucester,|Cape Cod,| Cape Cod, 
| England, | France, France, England, | Scotland, Zool., Mass., Mass., Mass., 
Character. ; many, 5 
| _ 1863, 1847, 1885, 1874, 1859, _ 1884, Cambridge, 1870, 1880 No. 16045 
Flower. | Fischer. | Delage. Menge. Murie. |Struthers.|| Mass.) Dwight. | (Albany). |U.S. N. M. 
s 
Neural spine appears s | > 
last on vertebra No. — 52 5! | 51 (?) ) 50 51 or 52 52 51 50 
Last distinct diapophy- | 
sis on vertebra a le ae 5° 51(?) | 49(?) 51 | 48or49 49 49 = 48 
: | | 
First perforated dia ) 
Ro ae on vertebra i 44 42 44(?) | — 44 44 44 45 = 43 
OL pew cence neve 
First complete inferior 
arterial foramen on — — = | = 49 49 50 50 a 50 
vertebra No....-... 
